LETTERS

In the article “Vitrectomy for DME Without Macular Traction,” by Takao Hirano and Toshinori Murata (June 2013), the editors may have made an error or perhaps simply misjudged in formatting. I doubt whether much can be done now, but I thought I would point it out nevertheless.

On the first page of the article, an enlarged quote appears: “Deterioration of vision in eyes with DME is directly associated with an increase in central macular thickness, but resolution of edema following vitrectomy does not necessarily lead to visual recovery.”

Technically, this is true. However, it was also the thrust of the paper, as well as the guest editorial and the twopart series that Drs. Veronica Kon Graversen, Michael Stewart, and I submitted, that this concept, stated in this way, can be misleading (and counter to the main point of all these related articles), although the DRCR.net studies of this subject have widely promulgated the concept.

To put it bluntly, we believe the DRCR.net studies^{1, 2} on this topic (even including disclaimers) got it wrong. No level 1 evidence exists showing early vitrectomy is not every bit as good as, or perhaps possibly superior to, other forms of treatment of DME.

ERRATA In the June 2013 issue, an incorrect version of Figure 1 was published with Takao Hirano and Toshinori Murata’s article “Vitrectomy for DME Without Macular Traction.” The correct figure appears here. In July/August 2013 issue, one of the authors of the peer-reviewed article “Newer Molecular Targets For the Management of DME” was incorrectly identified as Ashish G. Sharma. While there is a Dr. Ashish G. Sharma practicing retina with Retina Consultants of Southwest Florida, the Dr. Sharma who co-authored this article does not use a middle initial. Retinal Physician regrets these errors.

No proof exists that eyes with DME, but with good remaining visual potential (as determined by SD-OCT), won’t do just as well with vitrectomy as with other forms of treatment.

The reason the enlarged quotation and the conclusions of the DRCR.net studies are misleading is that DRCR.-net performed the studies before clinicians had the capability to predict which eyes had a significant chance at recovery if the macular edema resolved — ie, their outer retinas were relatively intact, before vitrectomy.

At the time of these studies, it was still not possible to predict preoperatively which eyes had good or not good prospects of visual recovery after vitrectomy, due to irrevocable damage to their outer retinas by the time they underwent vitrectomy.

Only with SD-OCT (approved in 2006) could patients with reasonably good prognoses undergo vitrectomy and have a hope of good results, exactly as we predicted, and as Drs. Hirano and Murata have shown.

The DRCR.net studies performed vitrectomies only in eyes with end-stage DME that failed multiple treatments. Many of these eyes may have had no real potential for improved VA, even when vitrectomy resolved the edema, which it typically did.

Our goal has always been to propose that early vitrectomy for DME is a reasonable option and that the final answer is not yet in, despite the DRCR.-net publications suggesting vitrectomy is not a good choice compared to other treatment options presently available.

We still feel that way.

Maurice B. Landers, III, MD Chapel Hill, NC

REFERENCES

1. Diabetic Retinopathy Clinical Research Network Writing Committee; Haller JA, Qin H, Apte RS, et al. Vitrectomy outcomes in eyes with diabetic macular edema and vitreomacular traction. Ophthalmology. 2010;117:1087-1093.

2. Flaxel CJ, Edwards AR, Aiello LP, et al. Factors associated with visual acuity outcomes after vitrectomy for diabetic macular edema: diabetic retinopathy clinical research network. Retina. 2010;30:1488-1495.

CO-AUTHOR’S RESPONSE

Iam grateful to Dr. Landers for his comments. For European and Japanese patients, I believe the effectiveness of vitrectomy to resolve DME is widely accepted, so warning that “Deterioration of vision in eyes with DME is directly associated with an increase in central macular thickness, but resolution of edema following vitrectomy does not necessarily lead to visual recovery” serves well as an indicator of the need to confirm photoreceptor integrity by preserving the IS/OS line and ELM.

Because I am Japanese, I did not notice this comment could be misleading. Nevertheless, many Americans, presumably a majority of readers, may have believed vitrectomy does not work.

Toshinori Murata, MD Matsumoto, Japan

I’d like to congratulate Dr. Landers et al on their two-part article, published in May and June 2013, calling for a controlled study of early PPV in DME.

We recently published articles^{1, 2} on extrafoveal traction in diffuse DME, RVO, and other entities with macular edema. The studies showed the relatively high prevalence (eg, one-third of the eyes with diffuse DME) of extrafoveal traction without vitreofoveal traction.

Detection of this traction was mainly based on the 3D characteristics of SD-OCT. Relevant 3D video clips are presented in these articles. In contrast, the prevalence of extrafoveal traction in diffuse DME using TD-OCT was 11%.

It is worth mentioning that the high prevalence of extrafoveal traction seemed to coincide with the relatively high prevalence of detectable extrafoveal traction membranes during PPV, which often go undetected preoperatively on OCT.

In that regard, we recently also presented the continuation/unification of diabetic ERM with the posterior hyaloid in DME,³ so we very much agree that a controlled PPV study might improve our understanding and would likely result in better outcomes in eyes with diffuse DME.

Avinoam Ophir, MD Hadera, Israel

REFERENCES

1. Ophir A, Martinez MR, Mosqueda P, Trevino A. Vitreous traction and epiretinal membranes in diabetic macular oedema using spectral-domain optical coherence tomography. Eye (Lond). 2010;24:1545-1553.

2. Martinez MR, Ophir A. Extrafoveal traction in retinal vein occlusion using spectral domain optical coherence tomography. Graefes Arch Clin Exp Ophthalmol. 2011;249:811-820.

3. Ophir A, Martinez MR. Epiretinal membranes and incomplete posterior vitreous detachment in diabetic macular edema, detected by spectral-domain optical coherence tomography. Invest Ophthalmol Vis Sci. 2011;52:6414-6420.